Monday, Kevin Garnett celebrated his 38th birthday. Unbelievably, Garnett entered the league as a rail-thing 18-year-old who was trying to avoid center designation by jokingly saying he was 6-foot-12.

The past 19 season have been a joy to watch as Garnett revolutionized the NBA with his ability to step out and hit jumpers and take power forwards off the dribble. He was a madman on the glass and an incredible leader, driving some awful Timberwolves teams into the Playoffs. When he finally got his chance to compete for a title with the Celtics in 2008, he was already coming off his prime but had enough to get his team to two NBA Finals in three years.

Garnett is one of the best players of his generation. His impact and his intensity are still seen all over the league. It is not a coincidence so many players go up to goaltend block shots taken after the buzzer. That “no prisoners, no easy shots given” attitude is something Garnett helped maintain throughout the inefficient 2000s and into the analytics 2010s. There is still something romantic about a player who is all will and determination.

But that career is coming to its end soon. All that will be left are these little fingerprints.

And if you are a Nets fan, those little fingerprints are going to be what will have to sustain the growth and maturation of a rookie like Mason Plumlee.

Plumlee was a revelation as the 22nd overall pick in last year’s Draft. Everyone knew he would be a grinder around the basket with his offense limited virtually to dunking. He averaged 7.4 points per game and 4.4 rebounds per game as a rookie, gaining confidence and becoming a big contributor as the season went on.

It culminated with that that game-saving block of LeBron James against the Heat in early April.

“I think [Plumlee’s] confidence has come from his play with the fact that he watches film and he is real with himself,” Garnett said of Plumlee. “That fact that he can evaluate himself and his mistakes and learn from them. We are trusting him. He is finishing plays and being effective. Everything is a credit to him. He busts his behind and he works very , very hard. Him and Coach [Roy] Rogers are at it every day and I told him that if you want to be better, that is what you have to do.”

Garnett has had his influence too, even if he is not directly working with Plumlee. It has to be valuable to see a professional like Garnett work at his craft. That has most likely made him a better player and contributed to his success. Garnett’s mean mugs and intense glare probably did not hurt either.

It is hard to say what the future will hold for either Garnett or Plumlee at this point in the offseason for the Nets.

Garnett is slated to become a free agent after the 2015 season. But the whispers have begun with Paul Pierce hitting the market that Garnett may hang it up and leave that $12 million owed on the table. That would free up time to play Plumlee more as a backup to Brook Lopez — another player who could use some of KG’s tutelage.

Plumlee himself has a lot of improvements he needs to make to become a consistent rotation player in the NBA. Right now, he is a backup center and a good young one to have. He will have to continue to learn and grow, gleaning as much as he can from Garnett to continue building on the success he had this year.

For now, Plumlee has to take everything he has learned his rookie year and put it to work on himself. It seems he is already a willing pupil, ready to learn and contribute to the Nets for years to come.